The Siemens SIRIUS 3RH1131-2UB40 is a size S00 auxiliary contactor with a 24 VDC coil, rated for 10 A at 24 V. It carries 3 normally-open instantaneous contacts and 1 normally-closed contact, with no leading, lagging, or make-before-break switching. The coil draws 3.2 W closing and holding power, with a built-in varistor surge suppressor. Front protection is IP20; the unit mounts via screw or snap-on onto a DIN rail, with ±180° rotation possible on a vertical surface.
Ratings and what they mean for fit
The 10 A rating at 24 V is the thermal current for the auxiliary contacts — this governs the continuous current the contacts can carry in a control circuit, not a motor load. For higher voltages the rating derates: 6 A at 230 V, 3 A at 400 V, 2 A at 500 V, and 1 A at 690 V. The 1 A rating at 110 V and 0.27 A at 220 V are for DC switching, which is significantly lower due to arc extinction limits. The contact reliability spec — one incorrect switching per 100 million operations at 17 V, 1 mA — means this contactor handles dry-circuit (low-energy) signals reliably, important for PLC inputs or safety relay chains. The surge voltage resistance of 6 kV and pollution degree 3 rating mean the contactor is suitable for industrial panels where transient overvoltages and conductive dust are present. The operating temperature range of -25 to +60 °C covers most indoor panel environments; storage and transport range of -55 to +80 °C is broader for logistics.
Panel integration
The 45 mm width and 73 mm depth fit standard DIN-rail enclosures. The screw and snap-on fastening method allows tool-free installation on a 35 mm rail. The S00 contactor size is the smallest Siemens frame, so it occupies minimal panel space. The IP20 front means it is protected against finger contact but not washdown — keep it inside a closed panel.